diff --git a/packages/osc/src/bundle.ts b/packages/osc/src/bundle.ts
index dc59d09..9d527ba 100644
--- a/packages/osc/src/bundle.ts
+++ b/packages/osc/src/bundle.ts
@@ -1,6 +1,6 @@
-import { messageFromBuffer, messageToBuffer } from './message';
-import { OSCBundle } from './models';
-import { oscTypeConverterMap } from './osc-types';
+import { messageFromBuffer, messageToBuffer } from './message.js';
+import { OSCBundle } from './models.js';
+import { oscTypeConverterMap } from './osc-types.js';
 
 export function bundleFromBuffer(bytes: Uint8Array): [OSCBundle | undefined, Uint8Array | undefined] {
   if (bytes.length < 20) {
diff --git a/packages/osc/src/index.ts b/packages/osc/src/index.ts
index d1761d6..3b83a74 100644
--- a/packages/osc/src/index.ts
+++ b/packages/osc/src/index.ts
@@ -1,10 +1,10 @@
-import { bundleFromBuffer } from './bundle';
-import { messageFromBuffer } from './message';
-import { OSCBundle, OSCMessage } from './models';
+import { bundleFromBuffer } from './bundle.js';
+import { messageFromBuffer } from './message.js';
+import { OSCBundle, OSCMessage } from './models.js';
 
-export * from './models';
-export * from './message';
-export * from './bundle';
+export * from './models.js';
+export * from './message.js';
+export * from './bundle.js';
 
 export function fromBuffer(bytes: Uint8Array): [OSCBundle | OSCMessage | undefined, Uint8Array | undefined] {
   if (bytes[0] === 47) {
diff --git a/packages/osc/src/message.ts b/packages/osc/src/message.ts
index cb81f13..378f085 100644
--- a/packages/osc/src/message.ts
+++ b/packages/osc/src/message.ts
@@ -1,5 +1,5 @@
-import { OSCMessage, OSCArg, OSCType } from './models';
-import { oscTypeConverterMap } from './osc-types';
+import { OSCMessage, OSCArg, OSCType } from './models.js';
+import { oscTypeConverterMap } from './osc-types.js';
 
 function argsToBuffer(args: OSCArg[]) {
   const argBuffers: Uint8Array[] = [];
diff --git a/packages/osc/src/osc-types.ts b/packages/osc/src/osc-types.ts
index de8084c..1540b39 100644
--- a/packages/osc/src/osc-types.ts
+++ b/packages/osc/src/osc-types.ts
@@ -1,4 +1,4 @@
-import { OSCTypeConverter, OSCTimeTag } from './models';
+import { OSCTypeConverter, OSCTimeTag } from './models.js';
 
 export const oscTypeConverterMap: { [key: string]: OSCTypeConverter } = {
   s: {